The world of software development is changing faster than ever before. Artificial intelligence (AI) has fundamentally changed the development life cycle. And expanding innovation and investment in technologies like machine learning (ML) and the internet of things (IoT) have impacted programming languages developers use every day.

In 2023, we witnessed significant shifts in the popularity of and demand for programming languages. New languages such as Dart, Vyper, and Kotlin have emerged to address the growing need for efficiency, blockchain development, and specialized use cases. 

Of particular note is the rapid growth of machine learning and AI tools, which have driven the popularity of languages like Python and C++.

So, which languages continue to hold sway in the tech industry? What languages should employers and developers be investing their time and energy in? To answer this question, HackerRank conducted an exhaustive study of developer preferences and language demand to create an unbiased list of the top programming languages. Here’s what we found.

Methodology

Our data comes from our 2024 Developer Skills Report, which combines survey responses from developers, employers, and recruiters with data from the HackerRank platform.

To identify language popularity, we analyzed which languages candidates selected for coding tests with multiple language options and their proficiency levels within each language. We’ve also measured the demand for each of these languages based on the number of tests created with the language in the test name. 

The data change rates reflect differences between volumes in 2022 and 2023. 

The Most Popular Programming Languages

#1. Python

What this language is used for: 

• Web development (back end)
• Data analysis and visualization
• AI and machine learning
• Scientific computing
• Numerical simulations
• Automation and scripting
• Game development

Python, a versatile and easy-to-read language, has surged in popularity for web development, data analysis, and artificial intelligence (AI) projects. It ranks number one in popularity and number two for employer demand—up 15% from 2022. 

Python’s variety of robust frameworks, clean syntax, and extensive libraries make it a top choice for beginners and seasoned developers. From building web applications to powering machine learning algorithms, Python’s popularity continues to grow. 

#2. C++

What this language is used for: 

• Game development
• High-performance applications
• Embedded systems (IoT devices)
• Graphics engines and rendering software
• Real-time simulations
• Financial applications

C++ is a fast and powerful programming language widely used in system software, game development, and high-performance applications. Its ability to directly interact with hardware and memory management gives it an edge in performance-critical scenarios. Despite being more complex than some languages, C++ remains a go-to choice for developers requiring high-speed computing. 

C++ is a top language for hardware-oriented applications, use cases that need fast rendering, and video game engines. It’s also commonly used for AI tasks that require control over memory management and intensive computations.

While it comes in second for developer popularity, C++ is the third most in-demand programming language, an 8% drop from 2022. 

#3. Java

What this language is used for: 

• Mobile applications 
• Enterprise applications
• Desktop GUI applications (IDEs and games)
• Back-end services
• Big data technologies (Hadoop and Spark)

Java, renowned for its platform independence and extensive libraries, remains a staple in enterprise applications, Android app development, and web services. Its “write once, run anywhere” approach is ideal for cross-platform development. Despite competition from newer languages, Java’s reliability and ecosystem ensure its continued relevance. 

When it comes to programming assessments, Java ranks first for demand. This is no surprise, given Java’s platform independence and well-tested ecosystem of libraries to assist development. Java remains a top coding language for enterprise-level software and applications. 

#4. SQL

What this language is used for:

• Querying and retrieving data from databases
• Creating and modifying database schemas
• Defining constraints to ensure data integrity

SQL is a widely-used structured query language for creating, defining, implementing, accessing, and managing relational databases. SQL stands out on this list as the only database-oriented language in a crowd of front-end and back-end languages.

SQL’s widespread use in database operations adds to its popularity, but its specialized focus restricts its broad adoption compared to more versatile languages like Python and Java. SQL climbed in rank to become the fourth most popular coding language among developers in 2023, though its total usage in programming language tests did decrease slightly during the same period.

#5. JavaScript

What this language is used for: 

• Web development
• Mobile development
• Interactive design
• Data visualization

JavaScript, known as the go-to language for web development, is crucial for making websites interactive and dynamic. While JavaScript is primarily a front-end programming language, popular frameworks like React and Node.js do extend its capabilities to back-end development. It also offers cross-platform development capabilities, especially with frameworks like React Native and Ionic, allowing developers to create mobile apps for iOS and Android using the same language.

JavaScript is widely favored by developers, ranking third in popularity and seventh in employer demand. However, JavaScript demand might be underreported, as employers could be assessing competency in this skill with more generalized test questions that test a variety of skills.

#6. C

What this language is used for: 

• Embedded systems
• Application software
• High-performance computing

It’s no surprise that C remains among the top 10 most popular coding languages. C is a powerhouse in the programming world, known for its efficiency and versatility. It’s the go-to language for tasks where speed and direct hardware access are critical.

One of its key applications is in embedded systems—think of the software running on your smartwatch or controlling the sensors in your car. C’s ability to communicate directly with hardware makes it indispensable.

C ranked sixth, remaining in the same position from 2022 to 2023. However, C didn’t manage to make the top 10 of the most in-demand coding assessment languages. While C continues to be important for specific applications and industries, its demand seems lower than other programming languages due to complexity, safety concerns, and the abundance of alternatives.

#7. C#/.NET

What this language is used for: 

• Game development
• Desktop application development 
• Mobile app development 

C# and the .NET framework, developed by Microsoft, are popular for building desktop applications, web services, and games on the Windows platform. 

What sets C# apart is that it’s a strongly typed language, helping developers avoid errors and bugs in their code. Pair that with the extensive libraries and tools offered by the .NET framework, and the seamless integration with Visual Studio, and you’ve got a winning combination that’s favored by Windows developers far and wide.

Despite competition from cross-platform alternatives, C#/.NET’s ecosystem and tooling make it an indispensable language for many developers. Companies that have adopted C# include Bloomberg, Dell, and Siemens.

C# ranks seventh for developer popularity. However, when it comes to demand in real-world assessments, it secures the fifth spot. This underscores its practical appeal and reliability in delivering tangible results, making it a cornerstone programming language.

#8. Go

What this language is used for: 

• Web development
• Systems programming 
• Cloud services

Go, or Golang, is a modern, statically typed language developed by Google. Known for its simplicity, concurrency support, and efficiency, Go is popular for cloud computing, microservices, and back-end development. Despite being relatively new, Go’s performance and growing ecosystem make it a promising choice for scalable applications. 

Since its launch in 2009, interest and demand have continued to grow. Between 2018 and 2020, Go was the top language developers wanted to learn. In 2023, Go rose in popularity, landing eigth on our list, and it remains within the top 10 in-demand programming languages. Tech giants like Uber, Docker, Dropbox, and Twitch have adopted Go to manage data and provide creative solutions. 

#9. PHP

What this language is used for: 

• E-commerce websites
• API development (Laravel and Symfony)
• Content management systems

PHP, a server-side scripting language, is essential for creating dynamic websites, content management systems (CMS), and e-commerce platforms. Despite its critics, PHP’s ease of use, extensive frameworks like WordPress, and compatibility with various web servers maintain its popularity.

PHP remains within the top 10 for both popularity and demand. However, its popularity among developers did decrease in 2023, dropping from eighth to ninth. 

#10. TypeScript

What this language is used for: 

• Mobile app development 
• Server-side scripting 
• Desktop applications 

TypeScript, a superset of JavaScript, adds static typing and tooling to the language. Popular for front-end development with Angular and React, TypeScript catches errors at compile time, enhancing code quality and maintainability. 

The robust tooling support, including features like code navigation, intelligent code completion, and automatic refactoring, makes TypeScript a solid coding language for developers and tech teams. Despite its learning curve, TypeScript’s benefits for large-scale applications are undeniable. 

Typescript rounds out the top 10 most popular coding languages among developers but did not manage to crack the top 10 for most in-demand languages. 

#11. Bash

What this language is used for: 

• DevOps
• Automation
• System maintenance
• Scripting operations on Unix-based systems

Bash (Bourne-Again SHell) is crucial for system administrators and DevOps engineers who use it to automate tasks and write shell scripts in Unix-based systems. Many developers are drawn to Bash for its simplicity, versatility, and efficiency in automating tasks and managing systems. Despite its age, Bash remains indispensable for managing Linux servers and executing automation scripts.

Bash rose in popularity among developers from 12th in 2022 to 11th in 2023.

#12. Swift

What this language is used for: 

• Apple products app development

Swift, developed by Apple, is the primary language for iOS, macOS, watchOS, and tvOS app development. Its safety features, speed, and integration with Apple’s ecosystem have made it popular among iOS developers. 

Swift’s popularity has declined slightly: from 2022 to 2023, it fell from 11th to 12th in preference among developers. Swift’s decline in popularity may have been influenced by the many competing languages, platform diversification, and the maturation of existing codebases. It also never managed to catch on as a general-purpose language. Unable to achieve broader popularity, Swift’s usage levels reflect its role as a specialized technology. 

#13. Kotlin

What this language is used for: 

• Server-side development 
• Desktop application and Android app development 
• Data science and analytics

Kotlin, a modern programming language from JetBrains, is interoperable with Java and favored for Android app development. Its concise syntax, null safety, and seamless integration with existing Java codebases have increased popularity among Android developers.

While Kotlin falls last on our developer popularity list, its demand is noticeably higher than its popularity, ranking ninth in employer demand. Given its adoption by major companies like Netflix, Google, and JetBrains, Kotlin presents a compelling choice for developers and tech teams to consider.

The post The Most Popular Programming Languages of 2024 appeared first on HackerRank Blog.

In 2010, developer tool vendor JetBrains set out to address some of the common challenges and pitfalls faced by developers using Java and other programming languages. They wanted to design a language that was more expressive, concise, and safer, ultimately improving developer productivity and satisfaction. The result was Kotlin, a modern programming language that has transformed the way developers approach coding. 

In this article, we’ll take a closer look at what makes Kotlin stand out, its key features and advantages, its use cases, and the skills tech teams need to get the most out of this versatile language. Whether you’re a hiring manager, tech recruiter, or a tech professional, this article will provide you with valuable insights into the world of Kotlin.

What Is Kotlin?

Released in July 2011 under the name Project Kotlin, Kotlin is a statically typed programming language that runs on the Java Virtual Machine (JVM) and is designed to be fully interoperable with Java. This means developers can use the vast ecosystem and libraries of Java while also taking advantage of Kotlin’s more modern features and syntax. Kotlin also eliminates much of the boilerplate code required in Java, making it easier to write clean, reliable code. 

Kotlin’s most notable impact, however, has been in the realm of Android development, where Java was the go-to language for years. Google announced official support for Kotlin on the Android platform in 2017 and has since been moving more and more toward a “Kotlin-first” approach to Android development. Today, over 60% of Android developers have adopted Kotlin as their language of choice, and it is used in 95% of the top 1,000 Android apps. 

But Kotlin’s capabilities extend beyond just Android development. Its concise syntax, powerful features, and interoperability with Java make it an excellent option for a wide range of applications ranging from server-side development to web development.

Key Features of Kotlin

Kotlin brings together the robustness and universality of Java with the modern touch and simplicity that today’s developers crave.

Conciseness

Kotlin is designed to be more concise than Java, which means developers can write less code to achieve the same functionality. This is possible due to Kotlin’s support for type inference, which allows the compiler to infer the data type of a variable or expression based on its context. This eliminates the need to explicitly declare the data type in many cases, reducing boilerplate code. For example, in Java, you might write: List<String> myList = new ArrayList<String>();

In Kotlin, you can simply write: val myList = ArrayList<String>()

Safety

Kotlin is designed with safety in mind and includes several features that help prevent common programming errors. For example, Kotlin’s type system is designed to eliminate the dreaded null pointer exception, which is a common source of runtime errors in Java. In Kotlin, all variables are non-nullable by default, and you must explicitly declare a variable as nullable if you want it to be able to hold a null value. This makes it much easier to write safe, reliable code.

Interoperability

One of Kotlin’s biggest strengths is its interoperability with Java. Kotlin code can be easily mixed with Java code in the same project, and you can call Kotlin code from Java and vice versa. This makes it easy to gradually adopt Kotlin in an existing Java project, or to use Java libraries in a Kotlin project. For example, you can use the following Kotlin code to call a Java method: val result = MyJavaClass().myJavaMethod()

Tool-friendly

Kotlin is well-supported in a range of development tools and integrated development environments (IDEs). For example, Kotlin is fully supported in Android Studio, which is the official IDE for Android development. This means that you can take advantage of all the powerful features and tools in Android Studio when developing Kotlin code. Additionally, Kotlin has excellent support in other popular IDEs like IntelliJ IDEA and Eclipse.

In the next section, we’ll take a closer look at some of the advantages of Kotlin over other programming languages.

Advantages of Kotlin

Faster Development

Thanks to its conciseness, simplicity, and powerful tools, Kotlin can significantly speed up the development process. Developers can write less code and achieve more functionality, reducing the time and effort required to build software. This is especially beneficial in the fast-paced tech industry, where time to market can be a critical factor in the success of a project.

Improved Code Quality

Kotlin’s safety features and modern syntax contribute to better code quality. By reducing the likelihood of common programming errors such as null pointer exceptions, Kotlin helps to make software more reliable and robust. Moreover, the modern, expressive syntax of Kotlin makes code easier to read and maintain, further improving the quality of the software.

Developer Satisfaction

Kotlin’s modern syntax, powerful features, and tool support contribute to a more enjoyable development experience. Developers can focus more on solving problems and building great software, and less on dealing with boilerplate code and common programming errors. This leads to higher developer satisfaction, which can translate into higher productivity and better-quality software.

Use Cases for Kotlin

The versatility of Kotlin makes it an excellent choice for a variety of projects, from mobile and server-side development to web development and beyond. Let’s delve into some of the key use cases for Kotlin.

Android Development

Kotlin has become the go-to language for Android app development since Google announced official support for Kotlin on the Android platform in 2017. The language’s features make it an ideal choice for building high-quality Android apps. Many of the top apps on the Google Play Store, including Airbnb, Netflix, and Uber, have been built with Kotlin.

Server-Side Development

Kotlin is also a popular choice for server-side development. It can be used with a variety of server-side frameworks, such as Ktor, to build scalable and performant web applications and APIs. Kotlin’s interoperability with Java means that you can take advantage of the vast ecosystem of Java libraries and frameworks when building server-side applications.

Web Development

Kotlin is not only great for Android and server-side development, but it also shines in web development. With Kotlin/JS, you can compile Kotlin code to JavaScript for front-end development. And for the back end, frameworks like Spring Boot have got you covered.

What’s exciting is the recent advancements in WebAssembly (Wasm) that have opened new doors for Kotlin in web development. JetBrains and Google now provide experimental support for Kotlin on WebAssembly, enabling faster performance and effective code sharing between Android and web platforms. Early experiments show Kotlin code running up to 2x faster on WebAssembly compared to JavaScript. This is indeed a game-changer for Kotlin developers venturing into web development.

Other Use Cases

Kotlin is a versatile language that can be used for a wide range of other applications, from data analysis and machine learning to game development and more. Its powerful features and modern syntax make it an excellent choice for any project where you would traditionally use Java.

Key Kotlin Skills

Developing with Kotlin requires a mix of technical and soft skills to truly leverage the language’s capabilities. Key skills Kotlin developers need include:

• Understanding of Kotlin Syntax and Concepts: This includes understanding how to work with data types, control flow, functions, and classes in Kotlin. A thorough knowledge of Kotlin’s syntax will enable developers to write clean, efficient, and effective code.
• Experience with Java and the JVM: Since Kotlin is interoperable with Java and runs on the Java Virtual Machine (JVM), experience with Java is highly beneficial. Understanding how Java and the JVM work will help developers write better Kotlin code and leverage the vast ecosystem of Java libraries and frameworks.
• Familiarity with Android Development: For those looking to use Kotlin for Android apps, familiarity with Android development concepts and tools is essential. This includes understanding how to work with the Android SDK, Android Studio, and related tools and libraries.
• Problem-solving Skills: Problem-solving is a crucial skill for any developer, and Kotlin developers are no exception. Developers should be able to think critically and solve complex problems efficiently.
• Communication and Collaboration: Finally, strong communication and collaboration skills are essential. Developers should be able to work effectively in a team, communicate ideas clearly, and collaborate with other team members to achieve common goals.

Harnessing the Power of Kotlin

It’s clear that Kotlin is on a trajectory to become even more integral in software development. With more developers and companies adopting Kotlin, the ecosystem around this powerful language continues to evolve and expand, opening up new possibilities and opportunities. By understanding how Kotlin works and the skills needed to leverage it, you’ll be well prepared to tap into the potential of this versatile language and set your projects up for success.

This article was written with the help of AI. Can you tell which parts?

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Despite the ever-evolving nature of web development, some technologies have firmly established themselves as long-standing pillars. CSS — or Cascading Style Sheets —  is one such technology that, since its inception in the late ’90s, continues to play a fundamental role in how we design websites today. CSS is the magic wand that transforms the fundamental structure of a webpage, built by HTML, into a visually compelling and user-friendly interface.

The technology’s widespread use – 97.1% of all websites use CSS – underscores its pervasive influence in shaping the internet’s look and feel. This ubiquity of CSS means there’s a constant demand for skilled CSS professionals who can leverage its potential to create engaging, responsive, and interactive web experiences.

However, with high demand comes high expectations. Employers are actively seeking developers who can use CSS to solve complex design problems, implement seamless user experiences, and efficiently manage styles across various device screens. Mastery over CSS, therefore, is a highly sought-after skill, essential for developers seeking to showcase their front-end prowess. And it’s a key consideration for recruiters aiming to bring in top-notch talent.

This post aims to guide you through a series of carefully selected and progressively more challenging CSS interview questions. We’ll provide comprehensive explanations and illustrative code snippets. Whether you’re a developer wanting to brush up your CSS skills or a hiring manager looking for the right questions to assess your candidates, this guide is designed to help you approach your next CSS interview with confidence.

Understanding CSS

When you land on a beautifully designed web page with dynamic visuals, attractive color schemes, and easy-to-navigate layouts, you’re witnessing the result of well-implemented CSS. CSS is a cornerstone of web development, and its main purpose is to describe how HTML elements should be displayed on the screen. 

CSS, along with HTML and JavaScript, forms the trinity of front-end web development. While HTML provides the structural skeleton of a webpage and JavaScript adds functionality, CSS is responsible for the aesthetics. It controls the layout of multiple web pages simultaneously, adjusts elements to different screen sizes, and applies consistent styling across a website. 

This language is stylesheet-based, which means you write rules that tell browsers how to render the HTML elements on a page. For example, you might use CSS to specify that all the heading elements on a website should be bold and blue, or that a specific paragraph should be indented and have a larger font size. 

CSS is not just about making websites look good; it also enhances the user experience. With it, developers can create responsive designs that adapt to different devices, improve load times by optimizing styles, and increase accessibility for users with special needs. 

But why does this all matter in an interview context? When technical teams are recruiting for roles that involve any aspect of front-end development, CSS knowledge is almost invariably a requirement. This is because understanding CSS is key to being able to create web applications that not only function well but also provide an excellent user experience. So, whether you’re a software engineer, a web developer, a UI/UX designer, or in any role that touches on the user interface, CSS should be in your wheelhouse.

The CSS Interview: What to Expect

A CSS interview is an opportunity for candidates to showcase their skills in transforming plain, static HTML into dynamic, visually appealing web interfaces. At the same time, it allows recruiters to assess whether a candidate can effectively use CSS to meet design specifications, troubleshoot layout issues, and enhance the user experience.

Interviews focusing on CSS will typically go beyond basic syntax and selectors, delving into advanced topics such as layout techniques (like CSS Grid and Flexbox), CSS preprocessors, animations, responsive design, performance optimization, and handling browser compatibility issues.

The types of questions asked can vary widely depending on the role and the company. For instance, a front-end developer position might include more in-depth questions about CSS animations and transitions, while a full-stack developer role could cover how CSS fits into the broader context of a project, including interactions with JavaScript and back-end technologies.

The roles that often require CSS skills are vast and varied. Besides the obvious front-end web developer and full-stack developer, other roles like UI/UX designers, software engineers, and even roles in marketing or SEO could require a firm understanding of CSS. In some interviews, you might be asked to write CSS code in real time or refactor an existing piece of CSS code. In others, you may need to review a snippet of CSS and HTML code and discuss how it could be improved for better efficiency and maintainability.

1. Implementing a Class for CSS Colors

This question examines a developer’s understanding of CSS colors, which play a crucial role in styling web pages, and their ability to model concepts using object-oriented programming.

Task: Write a JavaScript class called `CSSColor` that represents a color in CSS. This class should have a constructor that takes three arguments: red, green, and blue. It should also have a method called `toCSS()` that returns the color in CSS format.

Input Format: The constructor will take three integers, each representing the red, green, and blue components of the color. The `toCSS()` method will take no arguments.

Constraints:

• The values for red, green, and blue will be integers.
• Each value will be between 0 and 255, inclusive.

Output Format: The `toCSS()` method will return a string representing the color in CSS format.

Sample Input:

let color = new CSSColor(255, 0, 0);

Sample Output:

console.log(color.toCSS()); // "rgb(255, 0, 0)"

Sample Code:

class CSSColor {

    constructor(red, green, blue) {

        this.red = red;

        this.green = green;

        this.blue = blue;

    }

    

    toCSS() {

        return `rgb(${this.red}, ${this.green}, ${this.blue})`;

    }

}

Explanation

The `CSSColor` class has a constructor that sets the red, green, and blue properties of the class based on the arguments passed in. The `toCSS()` method then returns a string that formats these properties in the CSS rgb format.

This question challenges developers to demonstrate their understanding of CSS colors and their capacity to use object-oriented programming to represent real-world concepts. This kind of problem-solving ability is invaluable in a professional setting, where developers must often create custom abstractions to solve unique challenges.

2. Implementing a Function to Apply CSS Styles

This question delves deeper into a developer’s knowledge of how CSS styles are applied to HTML elements through JavaScript. This checks their capability to manipulate the Document Object Model (DOM), an essential skill for building interactive web applications.

Task: Write a JavaScript function called `applyStyles` that takes a CSS selector and a style object as inputs and applies the styles to all elements that match the selector.

Input Format: The function will take two arguments: a string representing a CSS selector and an object where the keys are CSS properties and the values are the desired styles.

Constraints:

• The CSS selector will be a valid string selector.
• The style object will contain at least one property-value pair.

Sample Input:

applyStyles('p', { color: 'red', fontWeight: 'bold' });

Sample Code:

function applyStyles(selector, styles) {

    let elements = document.querySelectorAll(selector);

    for (let i = 0; i < elements.length; i++) {

        for (let style in styles) {

            elements[i].style[style] = styles[style];

        }

    }

}

Explanation:

The `applyStyles` function uses the `querySelectorAll` method to get all the elements that match the provided selector. It then iterates over these elements. For each element, it loops through each property in the styles object and assigns the corresponding value to that property on the element’s `style` object.

This question ups the difficulty from the previous one by not only requiring the candidate to work with CSS but also to manipulate HTML elements using JavaScript. It provides a good gauge of the candidate’s proficiency with JavaScript and their understanding of how CSS and JavaScript can interact in a web development context.

3. Implementing a Function to Rotate an Element

This question tests a developer’s expertise in transforming HTML elements using CSS, a powerful feature that allows developers to animate elements and create engaging user interfaces. 

Task: Write a JavaScript function called `rotateElement` that takes an HTML element’s id and a rotation angle as inputs and rotates the element to the specified angle.

Input Format: The function will take two arguments: a string representing the id of an HTML element and a number representing the rotation angle in degrees.

Constraints:

• The id will correspond to an existing HTML element.
• The rotation angle will be a valid number.

Sample Input:

rotateElement('myDiv', 45);

Sample Code:

function rotateElement(id, angle) {

    let element = document.getElementById(id);

    element.style.transform = `rotate(${angle}deg)`;

}

Explanation:

The `rotateElement` function uses the `getElementById` method to find the HTML element with the specified id. It then applies a rotation transformation to this element by setting its `transform` style to `rotate(${angle}deg)`, where `${angle}` is replaced with the provided angle.

This question requires an understanding of CSS transformations, which are a complex but powerful feature of CSS. Knowing how to use these transformations is crucial for creating modern, dynamic web pages. It also continues to test the candidate’s proficiency with JavaScript, particularly their ability to manipulate HTML elements and CSS styles.

4. Implementing a Function to Create a Grid Layout

This question delves into the developer’s knowledge of CSS grid layout, an advanced and powerful tool for creating responsive web layouts. It also tests their ability to generate HTML elements dynamically with JavaScript.

Task: Write a JavaScript function called `createGrid` that takes two arguments: the number of rows and the number of columns. The function should create a grid of `div` elements with the specified number of rows and columns and apply CSS grid layout to arrange these divs into a grid.

Constraints: Both the number of rows and columns will be positive integers.

Sample Input:

let grid = createGrid(3, 3);

Sample Code:

function createGrid(rows, columns) {

    let grid = document.createElement('div');

    grid.style.display = 'grid';

    grid.style.gridTemplateRows = `repeat(${rows}, 1fr)`;

    grid.style.gridTemplateColumns = `repeat(${columns}, 1fr)`;

    

    for (let i = 0; i < rows * columns; i++) {

        let cell = document.createElement('div');

        cell.textContent = `Cell ${i + 1}`;

        grid.appendChild(cell);

    }

    

    return grid;

}

Explanation:

The `createGrid` function begins by creating a new div element and setting its display style to ‘grid’. It then uses the CSS `gridTemplateRows` and `gridTemplateColumns` properties to define the grid’s structure, using the `repeat` function to create the specified number of rows and columns.

The function then enters a loop that runs once for each cell in the grid. In each iteration, it creates a new div, sets its text content to indicate its position, and appends it to the grid.

Finally, the function returns the grid element, which now has the desired grid structure and contains the appropriate number of cells.

This question raises the difficulty by requiring candidates to generate HTML elements dynamically and style them with an advanced CSS feature: the grid layout. This represents a practical task that developers might often face when creating complex, responsive web layouts.

5. Implementing a Function for Responsive Design

In this question, we’re testing the developer’s knowledge of CSS media queries, an important tool for creating responsive designs that adapt to different screen sizes. 

Task: Write a JavaScript function named `createResponsiveDiv` that creates a `div` element. This `div` should be styled such that it is 100% of the browser window’s width when the window is less than 600px wide and 50% of the browser window’s width otherwise.

Input Format: The function takes no arguments.

Constraints: The browser window’s width will be a positive number.

Output Format: The function will return an HTML `div` element that is styled according to the responsive design requirements.

Sample Input:

let responsiveDiv = createResponsiveDiv();

Sample Code:

function createResponsiveDiv() {

    let div = document.createElement('div');

    let style = document.createElement('style');

    style.innerHTML = `

        #responsiveDiv {

            width: 100%;

        }

        @media (min-width: 600px) {

            #responsiveDiv {

                width: 50%;

            }

        }

    `;

    document.head.appendChild(style);

    div.id = "responsiveDiv";

    return div;

}

Explanation:

The `createResponsiveDiv` function starts by creating a new `div` element. 

Next, it creates a `style` element and sets its innerHTML to the desired CSS. This CSS first sets the width of the `div` (which will be given the id “responsiveDiv”) to 100 percent. Then, it uses a media query to change this width to 50 percent if the width of the viewport is at least 600px. The style element is then appended to the `head` of the document.

Finally, the function gives the `div` the id “responsiveDiv” and returns it.

This question is the most challenging yet, requiring a strong understanding of media queries and how they can be used to create responsive designs. It also continues to test the developer’s skills in using JavaScript to create and manipulate HTML and CSS.

6. Implementing a Function to Apply a CSS Animation

This question evaluates a developer’s understanding of CSS animations, a sophisticated feature of CSS that’s fundamental to creating interactive and engaging web experiences. 

Task: Write a JavaScript function named `applyAnimation` that takes an HTML element’s id and applies a CSS keyframe animation to it. The animation should gradually change the element’s background color from red to blue over a period of 5 seconds.

Input Format: The function will take one argument: a string representing the id of an HTML element.

Constraints: The id will correspond to an existing HTML element.

Sample Input:

applyAnimation('myDiv');

Sample Code:

function applyAnimation(id) {

    let element = document.getElementById(id);

    let style = document.createElement('style');

    style.innerHTML = `

        @keyframes colorChange {

            0% {background-color: red;}

            100% {background-color: blue;}

        }

        #${id} {

            animation: colorChange 5s;

        }

    `;

    document.head.appendChild(style);

}

Explanation:

The `applyAnimation` function starts by getting a reference to the HTML element with the specified id using the `getElementById` method.

Next, it creates a `style` element and sets its innerHTML to define a CSS keyframe animation named `colorChange`. This animation gradually changes an element’s background color from red to blue. The CSS also applies this animation to the element with the specified id and sets the animation’s duration to 5 seconds. The style element is then appended to the `head` of the document.

This question significantly raises the difficulty level by requiring the candidate to use CSS keyframes, a complex but powerful feature that is crucial for creating animations in CSS. 

7. Creating a CSS Variable Manipulation Function

The final question explores the developer’s knowledge of CSS Variables (or custom properties), a more advanced feature of CSS. Custom properties provide a powerful way to create reusable values in CSS, which can be manipulated via JavaScript.

Task: Write a JavaScript function named `changeTheme` that takes two parameters: an HTML element’s id and a string representing a color. The function should change the value of the CSS variable `–theme-color` for the specified element to the provided color.

Input Format: The function will take two arguments: a string representing the id of an HTML element and another string representing a color.

Constraints:

• The id will correspond to an existing HTML element.
• The color will be a valid CSS color.

Sample Input:

changeTheme('myDiv', 'purple');

Sample Code:

function changeTheme(id, color) {

    let element = document.getElementById(id);

    element.style.setProperty('--theme-color', color);

}

Explanation:

The `changeTheme` function begins by getting a reference to the HTML element with the specified id.

Then, it uses the `setProperty` method to change the value of the CSS variable `–theme-color` for that element to the provided color.

This question represents a culmination of the candidate’s CSS and JavaScript knowledge, requiring them to understand how to manipulate CSS variables — a feature that brings a lot of power and flexibility to CSS. CSS variables can help reduce repetition, provide better scalability, and even allow for things like theme switching in CSS.

Resources to Improve HTML Knowledge

• HackerRank CSS Skills Certification
• HackerRank Interview
• Tech Interview Prep: How To Ace Your Interview

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The post 7 CSS Interview Questions Every Developer Should Know appeared first on HackerRank Blog.

Behind every stunning website is a language that turns bare-bones HTML into immersive digital experiences. That language is CSS, or Cascading Style Sheets. Despite often flying under the radar, CSS plays an indispensable role in modern web development, transforming basic web pages into engaging, interactive, and visually appealing digital spaces.

But what exactly is CSS? And why is it so critical in web development? Furthermore, how important is it in today’s job market? These are the questions we’re about to tackle. In this article, we’ll explore CSS in depth, providing insight into its features, use cases, and significance in the current tech hiring landscape.

Understanding CSS

When we talk about web development, it’s essential to mention the three pillars that form the foundation of the web: HTML, CSS, and JavaScript. While HTML (HyperText Markup Language) provides the structure of a web page, CSS is the stylist that steps in to make that structure visually appealing. JavaScript, on the other hand, adds interactivity, but that’s a topic for another day. Today, we’re focusing on CSS, the designer of the web.

CSS didn’t always exist alongside HTML. In the early days of the internet, all styles had to be included inline with the HTML. This made code extremely difficult to manage, especially for larger websites. Recognizing this issue, the World Wide Web Consortium (W3C) introduced CSS in late 1996 as a way to separate content from presentation, drastically simplifying the development and maintenance process.

Let’s use a real-world analogy to explain this. Imagine you’re building a house. HTML would be the bricks and mortar providing the structure — walls, floors, and ceilings. CSS would be the interior design that dictates the paint, furniture, and lighting to highlight the houses’s features. In other words, CSS describes how HTML elements should be displayed.

CSS works by “selecting” HTML elements and then applying a variety of “properties” to those elements. For example, you can select all the paragraph elements (`<p>`) on a webpage and apply a font size of 14 pixels, a line height of 1.5, and a color of dark gray.

p {

    font-size: 14px;

    line-height: 1.5;

    color: darkgray;

}

This code tells the browser to render all paragraphs with those specific styles, giving a consistent and aesthetically pleasing look across the entire website. And the best part? If you decide later that you want to change the color or font size of your paragraphs, you simply update the CSS, and the changes are applied everywhere that style is used.

Key Features and Advantages of CSS

As we delve deeper into the world of CSS, you’ll soon realize that this language is more than just an aesthetic tool; it’s a powerful component of efficient and effective web development. Here’s why.

Maintainability and Reusability of Styles

By separating content (HTML) from presentation (CSS), you can apply consistent styling across your entire website with just a few lines of code. Want to change your site’s primary color or font? Update one CSS file and the changes ripple across your entire site, reducing both the time and effort required to maintain the website. 

For example, imagine you want all your headers (`<h1>`) to be blue and bold. Instead of defining these properties each time you create a new header, you define it once in your CSS:

h1 {

    color: blue;

    font-weight: bold;

}

Now, every `<h1>` tag on your website will be bold and blue.

Presentation Flexibility Across Different Devices

CSS enables responsive web design, meaning you can create websites that look and function well on any device — be it a smartphone, tablet, laptop, or large desktop screen. This flexibility is crucial in our increasingly mobile world, where users expect seamless online experiences regardless of device.

/* CSS code that applies only on screens smaller than 600px */

@media only screen and (max-width: 600px) {

    body {

        background-color: lightblue;

    }

}

In this example, the background color of the page will change to light blue on screens smaller than 600px wide.

Faster Page Load Times

By using external stylesheets (files with .css extension), you can reduce your site’s load time. The browser caches these external files once on the first visit and reuses them on subsequent pages, resulting in faster page loads. This advantage not only enhances user experience but also aids in search engine optimization.

Accessibility Enhancements

CSS is also an essential tool for enhancing website accessibility. By using CSS to control visual presentation, you can create a design that remains clear and functional even when users employ accessibility tools. For instance, those who use screen readers can still navigate your site effectively.

Use Cases of CSS

CSS, in its role as the stylist of the web, has far-reaching applications that can transform the user interface and user experience of a website. Let’s take a look at some key use cases.

Website Layout and Design

At its most basic, CSS defines the layout and design of a web page, such as color schemes, typography, spacing, and positioning of elements. For example, CSS can be used to create multi-column layouts, sticky headers, or footers, and manage the z-index (the stacking order) of different elements.

Animation and Interactivity

While JavaScript is typically associated with adding interactivity to a website, CSS isn’t far behind. With CSS, you can create animations and transitions that trigger on certain events like hovering, focusing, or clicking. You can change color, size, position, and many other properties to make your website more engaging.

Here’s a simple example of a CSS hover effect:

button:hover {

    background-color: green;

    transform: scale(1.1);

}

In this example, when the user hovers over a button, the button’s background color changes to green, and it slightly increases in size.

Responsive Design

As we touched on earlier, CSS is integral to creating responsive designs. With the use of media queries, CSS can adapt the presentation of a website depending on the characteristics of the device being used, providing an optimal viewing experience on everything from a smartphone to a large desktop monitor.

User Interface Customization

CSS can also be used to customize user interfaces in web applications, making interfaces more user friendly and accessible. For instance, it can help visually distinguish different types of information, make interactive elements more noticeable, or adjust the layout based on user preferences or abilities.

The Hiring Outlook for CSS Skills

The ongoing growth of the tech industry has ushered in an escalating demand for professionals with expertise in web technologies, with CSS skills proving to be highly desirable in the current job market. This demand isn’t confined to web developers or designers; it encompasses a broad spectrum of roles within the tech industry.

Among the sought-after technical skills, proficiency in CSS is a fundamental requisite for front-end developers who are accountable for everything a user sees and interacts with on a website. Interestingly, CSS isn’t just for developers. It’s noted that roles in digital marketing or content management often require, or at least benefit from, a working knowledge of CSS.

Beyond the realm of front-end development, numerous other roles value CSS proficiency. Positions like UX/UI designers and full-stack developers need a solid grasp of CSS. The adaptability of CSS makes it an invaluable skill for roles that involve web accessibility, responsive design, or performance optimization.

It’s also crucial to note that CSS doesn’t exist in a vacuum; it’s part of a larger ecosystem of web development skills. CSS knowledge can considerably augment skills in HTML, JavaScript, and various JavaScript libraries and frameworks like React or Angular. As CSS-in-JS solutions gain popularity, CSS proficiency becomes even more entwined with JavaScript capabilities. Furthermore, understanding CSS principles can also lead to more effective use of design tools like Adobe XD or Sketch, which frequently employ CSS-like properties.

With the ongoing dominance of web technologies and the steady growth of the internet, it’s safe to say that CSS expertise will continue to be a critical skill in the foreseeable future. Investing time in mastering CSS is more than just acquiring proficiency in a programming language; it’s securing a toolset that can amplify web experiences, heighten user engagement, and bolster digital success.

Key Takeaways

As we wrap up our journey through the world of CSS, it’s clear that this language is a cornerstone of modern web development. Its ability to style HTML elements, create responsive designs, enhance accessibility, and even add a dash of animation make it a robust and versatile tool for developers and designers alike.

The importance of CSS is also evident in the current job market. With the demand for web technologies continuing to rise, CSS skills have become highly desirable across various roles within the tech industry. Whether you’re a front-end developer, a UX/UI designer, or a digital marketer, knowing CSS can give you an edge.

But beyond its practical uses and career benefits, CSS also offers a creative outlet. It gives you the power to turn a basic HTML structure into an engaging, interactive, and visually appealing web experience. It’s this blend of technology and creativity that makes CSS such a fascinating language to learn and use.

So, whether you’re a hiring manager seeking to understand what skills to look for, a professional aiming to upskill, or a newcomer deciding which language to learn first, remember that CSS plays a pivotal role in shaping the internet. Understanding CSS isn’t just about knowing a language; it’s about understanding the web’s visual vocabulary. 

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HTML is an enduring pillar in the world of web development, continually proving its worth even as technologies advance. Its power, ubiquity, and simplicity make it an essential skill for any aspiring web developer. As the backbone of virtually all websites, a solid understanding of HTML can unlock numerous opportunities and serve as a valuable asset in the tech industry.

HTML is more than just a static markup language; it provides a structure that brings content to life on the web. Its proficiency provides developers with the ability to craft and control the visual and structural aspects of a webpage, resulting in an enriched user experience. Alongside CSS and JavaScript, HTML forms the triad that orchestrates every interaction between a user and a website.

For those preparing to ace an HTML interview, it’s imperative to extend beyond the basic tags and attributes. The real challenge lies in demonstrating the ability to leverage HTML in creating clean, accessible, and responsive web layouts, which is likely to be the focus of an interview scenario. 

In this post, we delve deeper into the importance of HTML, demystify what a typical HTML interview entails, and provide a sequence of progressively challenging HTML interview questions. These questions are designed to polish your HTML skills and prepare you for the kinds of problems you are likely to face in an interview setting. Ready to elevate your HTML game? Let’s dive in.

Understanding HTML

HTML, or HyperText Markup Language, stands as the bread and butter of web development and is the markup language used to structure and present content on the web. Despite not being a programming language, its impact is vast and fundamental to how we interact with the digital world. From the web pages we visit to the online forms we fill out to the buttons we click — behind the scenes, HTML is working its magic.

Unlike programming languages that have functions, loops, and logic, HTML uses a set of pre-defined tags to define the structure and semantic meaning of the web content. Everything from headings represented by `<h1>` to `<h6>` tags to paragraphs encapsulated within the `<p>` tags and links denoted by `<a>` tags come together to create the structure of a web page.

Example:

<h1>This is a heading</h1>

<p>This is a paragraph.</p>

<a href="http://www.example.com">This is a link</a>

However, HTML isn’t just about defining the structure. It’s about enhancing the accessibility and optimizing web content for search engines. The tags and attributes in HTML play a crucial role in making web content accessible to all users, including those using assistive technologies, and they help search engines understand the content and relevance of your web pages, improving your website’s SEO.

So, if you want to insert an image into a webpage, the `<img>` tag with the `src` attribute is used. This not only displays the image but also informs the browser and search engines about the presence of an image.

<img src="image.jpg" alt="A description of the image">

With this context, it’s clear that a robust understanding of HTML is vital for anyone looking to succeed in the field of web development, and it’s equally essential for those looking to hire the best talent. An HTML interview is where these expectations meet reality, where you demonstrate your ability to leverage HTML to create well-structured, accessible, and SEO-friendly websites. 

What Does an HTML Interview Look Like?

Stepping into an HTML interview can be an engaging, challenging experience, but can also be one full of opportunities to showcase your skills and knowledge. While HTML is often considered a basic skill for web developers, interviews centered around it can be far from simple.

An HTML interview is an opportunity to showcase how well you understand and can apply this essential web language. The questions can range from fundamental concepts like “What is the `DOCTYPE`?”, to more complex ones involving the creation of specific layouts or solving accessibility issues.

Coding tasks could involve creating semantic HTML structures, building responsive tables, or dealing with forms and validations. You may also be asked to explain how certain HTML elements affect SEO or web accessibility. You’re not just showcasing your knowledge of HTML tags and attributes, but demonstrating an understanding of when and why to use them, and how they interact with CSS, JavaScript, and browsers.

HTML interviews are not exclusive to front-end developer roles. Full-stack developers, software engineers, UX/UI designers, and even content strategists might find themselves facing HTML interview questions. Any position that involves the creation or manipulation of web content can potentially require a sound understanding of HTML. These roles often expect you to build or design web pages, fix UI bugs, or collaborate closely with developers, making HTML an essential skill.

Now that we’ve outlined what an HTML interview might look like and the roles that could require HTML skills, let’s move on to some interview questions. These questions range from intermediate to advanced, and each one gets progressively more challenging. Whether you’re a developer preparing for an interview or a recruiter seeking question inspiration, the following problems will serve as a beneficial resource. 

1. Semantic HTML

Semantic HTML is an essential concept in modern web development, focusing on using the correct tags to provide meaning to the content and improve accessibility and SEO. Understanding this concept is key for any developer who wants to write clean, accessible, and SEO-friendly code.

Task: The task here is to rewrite a simple HTML code snippet using semantic HTML tags. 

Input: An HTML snippet using non-semantic `div` tags.

<div id="header">This is the Header</div>

<div id="nav">This is the Navigation</div>

<div id="main">This is the Main Content</div>

<div id="footer">This is the Footer</div>

Constraints:

• Replace the `div` tags with appropriate semantic HTML tags.
• Do not change the content inside the tags.
• Do not add additional attributes to the tags.

Sample Answer

<header>This is the Header</header>

<nav>This is the Navigation</nav>

<main>This is the Main Content</main>

<footer>This is the Footer</footer>

Explanation

This task revolves around the use of semantic HTML. The goal is to replace the generic `div` tags with corresponding semantic tags that provide more information about the type of content they contain.

• `<header>` is a semantic HTML tag that is typically used to contain introductory content or navigation links. In this case, it replaces the `div` with the id of “header”.
• `<nav>` is used for sections of a page that contain navigation links. It replaces the `div` with the id of “nav”.
• `<main>` is used for the dominant content of the body of a document or application. It replaces the `div` with the id of “main”.
• `<footer>` is used for containing information about the author, copyright information, etc. It replaces the `div` with the id of “footer”.

Using semantic HTML tags in this way improves the accessibility of the webpage and helps search engines understand the content better.

2. Form Validation

Form validation is a critical aspect of web development. It enhances UX and security by ensuring that users provide the required information in the correct format before submitting a form. HTML5 introduced several form validation attributes that simplify this task.

Task: Create an HTML form that includes validation. The form should have the following fields:

• A “Name” field that is required and should accept only alphabetic characters.
• An “Email” field that is required and should accept a valid email address.
• A “Password” field that is required and should be at least 8 characters long.
• A “Submit” button to submit the form.

Constraints:

• Use HTML5 validation attributes.
• Do not use JavaScript or any external libraries for validation.
• Do not include any CSS. The focus is purely on HTML structure and validation.

Sample Answer

<form>

    <label for="name">Name:</label><br>

    <input type="text" id="name" name="name" pattern="[A-Za-z]+" required><br>

    <label for="email">Email:</label><br>

    <input type="email" id="email" name="email" required><br>

    <label for="password">Password:</label><br>

    <input type="password" id="password" name="password" minlength="8" required><br>

    <input type="submit" value="Submit">

</form>

Explanation

The task tests the understanding of HTML forms and the use of HTML5 validation attributes:

• The `required` attribute is used to specify that an input field must be filled out before submitting the form.
• The `pattern` attribute in the “Name” field uses a regular expression `[A-Za-z]+` to accept only alphabetic characters.
• The `type` attribute with the value `email` in the “Email” field enforces valid email input.
• The `minlength` attribute in the “Password” field enforces that the password should be at least 8 characters long.

The correct usage of these HTML5 validation attributes can significantly improve the user experience by providing instant feedback before the form is submitted, reducing the load on the server.

3. Accessible Tables

Accessibility is a critical aspect of web development. HTML provides tools for making your web content accessible to people with disabilities, and understanding how to use these tools is essential.

Task: Your task is to create an accessible HTML table for a class schedule. The table should have three columns: “Day,” “Subject,” and “Time.” It should have data for five days from Monday to Friday.

Constraints:

• Use appropriate tags to make the table headers readable by screen readers.
• Do not include any CSS. The focus is purely on HTML structure and accessibility.

Sample Answer

<table>

    <thead>

        <tr>

            <th scope="col">Day</th>

            <th scope="col">Subject</th>

            <th scope="col">Time</th>

        </tr>

    </thead>

    <tbody>

        <tr>

            <td>Monday</td>

            <td>Math</td>

            <td>9:00-10:00</td>

        </tr>

        <tr>

            <td>Tuesday</td>

            <td>English</td>

            <td>10:00-11:00</td>

        </tr>

        <tr>

            <td>Wednesday</td>

            <td>Physics</td>

            <td>11:00-12:00</td>

        </tr>

        <tr>

            <td>Thursday</td>

            <td>Biology</td>

            <td>12:00-1:00</td>

        </tr>

        <tr>

            <td>Friday</td>

            <td>History</td>

            <td>1:00-2:00</td>

        </tr>

    </tbody>

</table>

Explanation

The task is about creating an accessible table in HTML. The `table` element is used to create a table, while the `thead` and `tbody` elements are used to group the content in the table header and the body respectively. This can provide benefits for screen reader users.

Each row of the table is created using the `tr` element, and within these rows, the `th` element is used for table headers, and the `td` element is used for table data cells.

Importantly, the `scope` attribute is used in the `th` elements. The `scope=”col”` attribute makes it clear that these headers are for columns. This helps screen readers understand the structure of the table, making your table more accessible.

4. Embedding Content

One of the powerful features of HTML is the ability to embed various types of content, such as images, videos, and audio files. Understanding how to use these elements is crucial for creating rich, interactive web pages.

Task: Your task is to write HTML code to accomplish the following:

• Embed a YouTube video with the id “zxcvbnm.” It should autoplay when the page loads, but the sound should be muted.
• Below the video, place an image with the source URL “https://example.com/image.jpg” and an alt text “Example Image.”
• Finally, add a download link for a PDF file at “https://example.com/document.pdf” with the link text “Download PDF.”

Constraints:

• Use the appropriate HTML tags for each type of content.
• Do not include any CSS or JavaScript. The focus is purely on HTML structure.

Sample Answer

<iframe width="560" height="315" src="https://www.youtube.com/embed/zxcvbnm?autoplay=1&mute=1" frameborder="0" allow="autoplay"></iframe>

<img src="https://example.com/image.jpg" alt="Example Image">

<a href="https://example.com/document.pdf" download="document">Download PDF</a>

Explanation

This task assesses your ability to embed different types of content using HTML.

• YouTube videos can be embedded using the `iframe` tag. The `src` attribute is set to the URL of the video, which includes parameters for autoplaying (`autoplay=1`) and muting (`mute=1`).
• Images can be included using the `img` tag, where the `src` attribute specifies the image URL and the `alt` attribute provides alternative text for screen readers or in case the image can’t be loaded.
• A link for downloading a file can be created using the `a` tag. The `href` attribute specifies the file URL, and the `download` attribute is used to trigger the download action when the link is clicked. The link text is placed between the opening and closing `a` tags.

5. Understanding the DOM

The Document Object Model (DOM) is a crucial concept in web development. It provides a structured representation of the document and defines a way that the structure can be manipulated. A deep understanding of the DOM is essential for interactive web development.

Task

Consider the following HTML code:

<div id="parent">

    <div id="child1" class="child">Child 1</div>

    <div id="child2" class="child">Child 2</div>

    <div id="child3" class="child">Child 3</div>

</div>

How would you select and manipulate the DOM elements in the following situations?

1. Select the div with id “parent”.
2. Select all divs with the class “child”.
3. Change the text content of the div with id “child2” to “Second Child”.

Constraints:

• Provide the JavaScript code that would accomplish each task.
• You can use either plain JavaScript or jQuery.
• Do not modify the original HTML code.

Sample Answer

Using plain JavaScript:

// 1. Select the div with id "parent".

var parentDiv = document.getElementById("parent");

// 2. Select all divs with the class "child".

var childDivs = document.getElementsByClassName("child");

// 3. Change the text content of the div with id "child2" to "Second Child".

document.getElementById("child2").textContent = "Second Child";

Or, using jQuery:

// 1. Select the div with id "parent".

var parentDiv = $("#parent");

// 2. Select all divs with the class "child".

var childDivs = $(".child");

// 3. Change the text content of the div with id "child2" to "Second Child".

$("#child2").text("Second Child");

Explanation

This task is about understanding the DOM and how to manipulate it using JavaScript or jQuery:

• In JavaScript, `document.getElementById` is used to select an element by its id, and `document.getElementsByClassName` is used to select all elements with a specific class. To change the text content of an element, we can use the `textContent` property.
• In jQuery, we can use `$(“#id”)` to select an element by id and `$(“.class”)` to select elements by class. The `.text()` method is used to change the text content of an element.

6. Advanced Form Validation

HTML forms with complex validation rules can ensure that user input is not only present but also meets a specific format or set of conditions. The `pattern` attribute in HTML5 allows developers to define such rules using regular expressions.

Task: Modify the sign-up form from Question #2 to include the following changes to the password field: Password (required, at least 8 characters, must include at least one digit and one special character)

Constraints:

• Use the `pattern` attribute to define the new validation rules for the password.
• The form should not be submitted unless the password meets all the specified requirements.
• Do not include any CSS or JavaScript. The focus is purely on HTML structure and attributes.

Sample Answer

<form>

    <label for="name">Full Name:</label><br>

    <input type="text" id="name" name="name" required minlength="5"><br>  

    <label for="email">Email Address:</label><br>

    <input type="email" id="email" name="email" required><br>   

    <label for="password">Password:</label><br>

    <input type="password" id="password" name="password" required pattern="(?=.*\d)(?=.*[!@#$%^&*]).{8,}"><br>    

    <label for="bio">Bio:</label><br>

    <textarea id="bio" name="bio" maxlength="500"></textarea><br>    

    <input type="submit" value="Sign Up">

</form>

Explanation

In addition to the form creation and validation concepts explained in the previous question, this task introduces the `pattern` attribute:

• The `pattern` attribute is used to define a regular expression — the input field’s value is checked against this expression when the form is submitted. If the value does not match the pattern, the form cannot be submitted.
• The regular expression `(?=.*\d)(?=.*[!@#$%^&*]).{8,}` is used to enforce the new password rules: it ensures that the password has at least one digit (`(?=.*\d)`), includes at least one special character (`(?=.*[!@#$%^&*])`), and is at least 8 characters long (`.{8,}`).

This question tests the candidate’s understanding of complex form validation using HTML5’s `pattern` attribute and regular expressions, crucial for creating secure and user-friendly forms. For real-world applications, it’s important to note that client-side validation is not enough for security; server-side validation is also necessary.

7. Accessibility and ARIA

Web accessibility ensures that websites, tools, and technologies are designed and developed so that people with disabilities can use them. ARIA (Accessible Rich Internet Applications) is a set of attributes that help increase the accessibility of web pages, particularly dynamic content and user interface components developed with JavaScript.

Task: You are provided with the following HTML code for a custom dropdown menu:

<div id="dropdown" onclick="toggleDropdown()">

    <button>Menu</button>

    <div id="dropdown-content">

        <a href="#">Option 1</a>

        <a href="#">Option 2</a>

        <a href="#">Option 3</a>

    </div>

</div>

The dropdown content (`#dropdown-content`) is hidden by default and shown when the user clicks on the “Menu” button.

Make the necessary modifications to this HTML code to make the dropdown menu accessible using ARIA attributes.

Constraints:

• Use appropriate ARIA roles, properties, and states.
• Assume the function `toggleDropdown()` changes the visibility of `#dropdown-content` and the text of the button to either “Menu” (when the dropdown is closed) or “Close” (when the dropdown is open).

Sample Answer

<div id="dropdown" onclick="toggleDropdown()" role="menubar">

    <button id="dropdown-button" aria-haspopup="true" aria-controls="dropdown-content">Menu</button>

    <div id="dropdown-content" role="menu" aria-labelledby="dropdown-button">

        <a href="#" role="menuitem">Option 1</a>

        <a href="#" role="menuitem">Option 2</a>

        <a href="#" role="menuitem">Option 3</a>

    </div>

</div>

Explanation

ARIA attributes are used to improve the accessibility of the dropdown menu:

• The `role` attribute is used to describe what the purpose of a certain HTML element is. Here, we’ve used the roles `menubar`, `menu`, and `menuitem` to provide the dropdown and its items with semantics that assistive technologies can understand.
• `aria-haspopup=”true”` indicates that the button has a popup menu.
• `aria-controls=”dropdown-content”` indicates that the dropdown button controls the visibility of the `#dropdown-content`.
• `aria-labelledby=”dropdown-button”` establishes a relationship between the dropdown content and the button that controls it.

Remember, this is only part of making a dropdown menu accessible. Proper keyboard interactions would also need to be implemented with JavaScript for full accessibility. ARIA doesn’t change behavior, but it helps assistive technologies understand the purpose, state, and functionality of custom controls. 

If this question seems too difficult, we can select a less complex HTML interview question. Otherwise, it’s an excellent way to test candidates’ understanding of web accessibility, a crucial aspect of modern web development.

8. Working with HTML5 Canvas

The HTML5 `<canvas>` element is used to draw graphics on a web page. The drawing on a `<canvas>` must be done with JavaScript, making it a powerful tool to create graphics, animations, and even game assets.

Task: Using HTML5’s Canvas API, create a 500px by 500px `<canvas>` element that draws a red rectangle that is 200px wide and 100px tall at the center of the canvas.

Constraints:

• The dimensions of the `<canvas>` must be set to 500px by 500px using HTML attributes.
• The rectangle should be exactly centered both vertically and horizontally in the `<canvas>`.

Sample Answer

<canvas id="canvas" width="500" height="500"></canvas>

<script>

    var canvas = document.getElementById('canvas');

    var ctx = canvas.getContext('2d');

    var rectWidth = 200;

    var rectHeight = 100;

    ctx.fillStyle = 'red';

    ctx.fillRect((canvas.width - rectWidth) / 2, (canvas.height - rectHeight) / 2, rectWidth, rectHeight);

</script>

Explanation

• First, we create a `<canvas>` element with the specified width and height using HTML attributes. 
• Next, we use JavaScript to get a reference to the `<canvas>` and its drawing context, which we’ll need to draw on the `<canvas>`.
• The width and height of the rectangle are set to the specified values. 
• The `fillStyle` property of the context is set to `’red’`, which will be the color of the rectangle.
• Finally, the `fillRect()` method is used to draw the rectangle. This method takes four parameters: the x and y coordinates of the upper-left corner of the rectangle, and the width and height of the rectangle. To center the rectangle, we calculate the x and y coordinates as `(canvas.width – rectWidth) / 2` and `(canvas.height – rectHeight) / 2`, respectively.

This question tests a candidate’s familiarity with the HTML5 Canvas API, which is a powerful tool for generating dynamic graphics and animations in web applications.

Resources to Improve HTML Knowledge

• HackerRank Interview
• Tech Interview Prep: How To Ace Your Interview

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HTML, or HyperText Markup Language, is the backbone of nearly every web page you’ve ever visited. It’s the unseen hero, laying the groundwork for the web as we know it today and serving as the foundational structure for our online universe. 

But why is HTML so important? Think of a website like a house. The HTML is the house’s blueprint. It defines where the doors, windows, and walls go. Without it, you’re left with a pile of bricks, pipes, and wires — technically, all the parts of a house, but far from a livable structure.

In the realm of web development, HTML is the bedrock skill that any budding front-end developer must master. Whether you’re a hiring manager looking for the best talents, or a tech professional aiming to elevate your skill set, understanding HTML’s depth and breadth is critical.

In this article, we’ll guide you through the basics and key features of HTML as well as its advantages, use cases and place in the current tech hiring landscape.

What is HTML?

Contrary to common belief, HTML is not actually programming language. It’s a markup language, which means it’s used to structure content on the web. It lays down the foundation for web pages, allowing us to insert various types of content such as text, images, videos, and more into web pages.

HTML dates back to the early days of the web. Created in 1990 by Tim Berners-Lee, a computer scientist at CERN, HTML was initially a simplified subset of SGML (Standard Generalized Markup Language) intended to manage the hypertext documents on the World Wide Web. Over the years, HTML has evolved to become an extensive markup language with a wide range of elements and attributes, allowing for richer web content.

A web page built with HTML consists of a series of elements, defined using tags. These tags act as containers that tell your web browser how to display the content they enclose. For example, the ‘<h1>’ tag is used to define the largest heading, while the ‘<p>’ tag is used to define a paragraph.

Consider this simple HTML example:

<!DOCTYPE html>

<html>

<head>

  <title>My First Web Page</title>

</head>

<body>

  <h1>Welcome to My Web Page</h1>

  <p>This is a paragraph of text on my web page.</p>

</body>

</html>

In this snippet, we’ve defined a basic HTML structure. It has a `<title>` that will appear on the browser tab, an `<h1>` heading, and a `<p>` paragraph in the `<body>`. When opened in a web browser, this HTML file will display a web page with a heading and a paragraph of text.

Over the years, new versions of HTML have been released. At time of writing, HTML5 is the latest major version. Each new version introduces additional elements and attributes, offering more flexibility and capability to web developers around the globe. 

The core principle, however, remains the same: HTML is the cornerstone of many web pages, and its mastery is a must-have skill for anyone working on the web.

Key Features of HTML

HTML is deceptively simple, yet profoundly powerful. It’s this range of capabilities, packaged in an approachable syntax, that makes HTML a key player in web development. Let’s dive into some of its main features.

Tags and Elements

As mentioned earlier, the building blocks of HTML are tags. They surround and apply meaning to content. When a start tag, some content, and an end tag are combined, they form an element. For example, `<p>Hello, world!</p>` creates a paragraph element containing the text “Hello, world!”

Attributes

Attributes provide additional information about HTML elements. They come in pairs: a name and a value. The name is the property you want to set, and the value is what you’re setting it to. For instance, in `<img src=”image.jpg” alt=”A beautiful sunrise”>`, “src” and “alt” are attributes providing additional information about the image element.

Hyperlinks and Images

One of the most powerful features of HTML (and the web in general) is the ability to link to other web pages. This is done using the anchor tag `<a>`. For instance, `<a href=”https://www.example.com”>Visit Example.com</a>` creates a clickable link to example.com.

Similarly, images are embedded using the `<img>` tag. The source of the image file is specified in the ‘src’ attribute, like so: `<img src=”image.jpg”>`.

Forms and Input

HTML allows for user input through forms, making interactive web pages possible. Forms can contain input elements like text fields, checkboxes, radio buttons, and more. For instance, `<input type=”text”>` creates a text input field.

Here is a simple form example:

<form action="/submit_form" method="post">

  <label for="fname">First Name:</label><br>

  <input type="text" id="fname" name="fname"><br>

  <input type="submit" value="Submit">

</form>

This form contains a text input field and a submit button. When the user clicks the submit button, the form data is sent to the ‘/submit_form’ URL for processing.

These are just a few of the many features HTML offers. By combining these elements and attributes, developers can create a complex, interactive web page that serves virtually any purpose. In the hands of a skilled developer, HTML is a tool of endless potential.

Advantages of Using HTML

HTML is not the only technology used for building websites, but it is one of the most critical and universal. Its enduring popularity among web developers can be credited to several key advantages.

Accessibility

HTML was designed with accessibility in mind. The correct usage of HTML tags helps define content structure and hierarchy, which is used by assistive technologies such as screen readers to accurately interpret the page content. Tags like `<header>`, `<nav>`, `<main>`, and `<footer>` provide semantic meaning to content, making a website more accessible to all users.

Search Engine Optimization

Search engines like Google depend on HTML structure to understand and rank content. Properly used HTML tags help to clearly delineate the important parts of a web page, such as titles and headers, improving a website’s visibility in search engine results.

Ease of Learning and Use

One of the most significant advantages of HTML is its simplicity. Compared to many other languages, HTML is relatively straightforward to pick up, even for beginners. Its syntax is logical, and you can see the results of your code immediately in a web browser, providing instant feedback that aids learning and debugging. Moreover, you don’t need any special software to write HTML — a simple text editor is enough.

Wide Support and Compatibility

Being the standard markup language for web pages, HTML is supported by all major web browsers, including Google Chrome, Safari, Firefox, and Microsoft Edge. Additionally, HTML works seamlessly with other technologies like CSS (for styling) and JavaScript (for functionality), making it a flexible choice for any web development project.

Common Use Cases for HTML

Having highlighted what HTML is and its key advantages, it’s time to dive into its practical applications. Here are some common use cases for HTML.

Web Development

The most direct and prevalent use of HTML is in web development. According to a survey by W3Techs, 95.2% of all websites use HTML. From personal blogs to e-commerce sites, educational platforms to social media networks, HTML is everywhere. It provides the structure and content of web pages, making it a universal tool in the world of web development.

Email Templates

HTML is not only used for websites; it also plays a significant role in creating email templates. When you receive a marketing email with styled text, images, and links, that’s HTML at work. By utilizing HTML, companies can create visually engaging and interactive emails to communicate with their customers.

Browser-Based Games

HTML, in combination with JavaScript and CSS, is often used to create simple browser-based games. With the advent of HTML5, the capabilities of such games have significantly improved, introducing features like canvas rendering and improved animations, making web games more sophisticated than ever before.

Web Applications

HTML forms the basis of many web applications, whether they’re social networking sites like Facebook, streaming platforms like Netflix, or productivity apps like Google Docs. While these applications use a range of advanced scripting and technologies, they all rely on HTML for their basic structure and content delivery.

No matter where you turn on the internet, HTML is hard at work, shaping our digital experiences and interactions. Whether it’s a simple static web page or a complex web application, HTML is the foundation, making it an indispensable part of any web-related project.

Hiring Outlook for HTML Skills

The ubiquity of HTML makes the language a highly sought-after skill. Its fundamental role in web development makes it indispensable to the tech industry, but its influence doesn’t stop there. Virtually any sector with a digital presence values HTML expertise for tasks like enhancing web interfaces, improving user experiences, and driving e-commerce solutions.

The U.S. Bureau of Labor Statistics anticipates a robust job market for HTML skills, projecting a 23% increase in web development roles from 2021 to 2031, a rate much higher than the average for all occupations. This growth is spurred by the rising popularity of mobile devices and e-commerce, underlining the importance of HTML knowledge in the current job landscape.

However, while HTML is powerful on its own, combining it with other tech skills can significantly amplify job prospects. CSS, which works hand-in-hand with HTML to design web pages, is typically a requisite skill. Similarly, JavaScript, the go-to language for web interactivity, is highly desirable. In fact, experience working with the “web development trifecta,” as it’s often called, was the fifth most in-demand skill in our 2023 Developer Skills Survey. Knowledge of responsive design principles, back-end languages like Python or Java, version control systems like Git, and SEO best practices are also invaluable assets alongside front-end skills.

In a nutshell, HTML is more than just a coding language—it’s the backbone of the digital world. Its utility spans far and wide, making it a crucial skill for tech professionals and a top requirement for hiring managers across industries. Whether you’re an aspiring web developer or an employer in the hiring process, understanding the versatile role of HTML in today’s digital age is key.

Key Takeaways

HTML’s simplicity, wide-ranging compatibility, and utility across various platforms make it one of the most powerful tools in a web developer’s arsenal. But it’s not just for developers — anyone working with digital content, from content creators to digital marketers, can benefit from understanding HTML.

As the demand for digital skills continues to grow, HTML proficiency remains highly valuable and sought after by employers across many industries. Whether you’re a tech professional looking to expand your skills or a hiring manager seeking top talent, understanding the role and relevance of HTML is a must.

But let’s not forget that HTML is just one piece of the web development puzzle. CSS brings style to HTML’s structure, and JavaScript adds dynamic functionality to static HTML pages. By mastering these three core web technologies — HTML, CSS, and JavaScript — you’ll have a solid foundation for building virtually anything on the web.

In the world of tech, the only constant is change. But as the web continues to evolve, one thing remains certain: HTML is here to stay. 

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Imagine a language designed with one purpose in mind: to make programmers happy. A language whose sole intention was not just to serve the cold, hard logic of machines, but to cater to the human mind and heart behind the code. Enter Ruby, a programming language born out of a sheer desire for a more joyful coding experience.

Ruby’s story began in 1993 in Japan, with a man named Yukihiro Matsumoto, often referred to as “Matz”. Matz, a computer scientist who was more interested in humans than machines, set out to design a language that would make programmers happy and productive. Frustrated with the rigidity of existing languages, he dreamt of a language that was not only practical but also enjoyable to use.

Now 30 years old, Ruby has transformed from an obscure, niche language into a powerhouse of the programming world. It has nurtured one of the world’s most popular web development frameworks, Ruby on Rails, and has influenced a multitude of other programming languages. 

But what makes Ruby a gem in the vast world of programming languages? What are its key features and benefits, and where is it most commonly used? Let’s find out.

What is Ruby?

Ruby is a dynamic, open-source, object-oriented programming language. Being object-oriented means it emphasizes objects — self-contained modules of code that bundle behavior (methods) and state (attributes). It’s also interpreted, meaning the code is processed at runtime rather than being pre-compiled. This lends Ruby a great deal of flexibility, as code can be altered and executed on the fly.

In the world of programming languages, Ruby is considered high level because it abstracts away many of the complicated, low-level details that developers would otherwise have to manage manually. This abstraction allows developers to focus on problem-solving and application logic, rather than the nitty-gritty of memory management and processor utilization.

As an open-source project, Ruby benefits from an active and passionate community of developers who contribute to its evolution and maintenance. They ensure that Ruby continues to be an adaptable, forward-thinking language that keeps pace with the ever-changing tech landscape.

Ruby’s Key Features

Ruby comes packed with numerous features that make it a powerful language for all sorts of tasks. Here are some of the key ones:

Elegant and Readable Syntax

Ruby’s syntax is designed to be easily understood. This simplicity makes Ruby an excellent choice for beginners, while still offering the depth and flexibility that experienced developers appreciate. Ruby’s syntax has a clean, minimalist aesthetic. This visual appearance, combined with its readability, contributes to a more pleasant and less fatiguing coding experience.

Example:

puts "Hello, World!"

With this one-liner, you’re printing “Hello, World!” to the console. It’s that easy.

Pure Object-Oriented Design

Ruby is a purely object-oriented language. Everything — from integers to nil (Ruby’s version of null) — is an object, each with its own methods and properties.

Example:

5.times { puts "Ruby is object-oriented!" }

Here, `5` is an instance of the Integer class, and `times` is one of its methods. The block `{ puts “Ruby is object-oriented!” }` is passed to the `times` method, which executes it five times.

Dynamic Typing

In Ruby, variables are dynamically typed, meaning a variable can hold different types of objects during its lifecycle.

Duck Typing

If an object behaves like a certain type, Ruby treats it as that type. This “duck typing” lends further flexibility to Ruby, enhancing its expressiveness.

Metaprogramming

Ruby’s dynamic nature enables metaprogramming — the writing of code that generates other code. While this feature should be used judiciously, it can simplify complex tasks and reduce redundancy.

Example:

    class Person

      attr_accessor :name, :age

    end

    p = Person.new

    p.name = "Alice"

    p.age = 30

Here, `attr_accessor` is a metaprogramming method that creates getter and setter methods for the `name` and `age` attributes.

Flexibility

Ruby is highly flexible, allowing you to freely alter its parts. Existing parts can be extended or redefined depending on the user’s needs, fostering creativity and problem solving.

Blocks

Ruby provides functionality for blocks (also called closures), which are unnamed chunks of code that can be accepted as arguments by methods. This feature can greatly simplify code and make it more readable.

Example:

[1, 2, 3].each { |num| puts num * 2 }

In this example, the block `{ |num| puts num * 2 }` is passed to the `each` method of the array, and it prints each number multiplied by two.

Common Use Cases for Ruby

Ruby’s readability, flexibility, and power have led to its adoption in a number of use cases. Let’s take a look at some of the main areas where Ruby shines.

Web Development with Ruby on Rails

The Ruby on Rails framework has been pivotal in defining Ruby’s reputation in the realm of web development. Rails follows the principle of convention over configuration and emphasizes developer happiness. With Rails, you can build a full-stack web application, encompassing both front-end and back-end structures. Companies such as GitHub, Airbnb, and Shopify have built their platforms using Ruby on Rails.

Automation and Testing

Ruby’s readability and simplicity make it a common choice for automation scripts and testing. Frameworks like Capybara and RSpec provide powerful tools for automating browser actions and conducting behavior-driven development and testing.

Data Analysis and Prototyping

Ruby’s high readability and powerful libraries are well-suited to data analysis and prototyping. Ruby libraries like Daru for data analysis and manipulation and Numo for numerical computing offer powerful tools for data scientists and data analysts.

Building Domain-Specific Languages (DSLs)

Ruby’s flexibility, facilitated by features like blocks and metaprogramming, makes it a great language for building domain-specific languages (DSLs). DSLs allow developers to write code that’s easy to read and write, specific to a domain problem, such as testing, web routing, or text processing.

Application Deployment and Management with Ruby Tools

Ruby also shines in the area of application deployment and management. Tools like Capistrano simplify the deployment process, while Ruby-based configuration management tools like Chef and Puppet facilitate managing infrastructure.

Key Takeaways

Born out of a desire to make programming more productive and enjoyable, Ruby’s influence continues to reverberate throughout the tech world. From its distinct, human-centered syntax to its formidable metaprogramming capabilities, Ruby manages to strike a fine balance between simplicity and power.

It’s a tool that opens doors to an array of applications, such as web development, automation and testing, data analysis, prototyping, and more. Its versatility, coupled with the ability to construct domain-specific languages, empowers developers to come up with elegant solutions to both generic and niche problems.

For hiring managers and tech professionals, the hiring outlook for Ruby remains positive, despite the influx of new languages and technologies. Ruby’s relevance in the tech industry has remained fairly steady. Though we saw both developer interest and demand wane in 2022, Ruby still managed to hold on to its 14th position on our list of most in-demand programming languages (at least for now). The demand for Ruby developers is fueled by the continued popularity of the Ruby on Rails framework and the value that Ruby brings to various domains such as web development, data analysis, and infrastructure management.

Whether you’re a developer looking to expand your skills or a hiring manager seeking talent for your team, Ruby stands as a vibrant, versatile, and valuable part of the programming landscape. To echo the sentiments of its creator, Ruby is about making coding a joy. And there’s no doubt that this joy is reflected in the richness of its use cases, the strength of its community, and its robust presence in the tech industry.

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Amid the pantheon of programming languages, R holds a special place. While it may not boast the broad-based appeal of Python or the legacy status of Java, R has carved out a unique niche.

R’s domain? Data science and statistical computing. Developed by statisticians, for statisticians, R brings together an unmatched suite of tools for data manipulation, analysis, and visualization. This makes R an exceptional asset for professionals in fields that need to make sense of data, from business and healthcare to research and beyond.

Unveiling the strength of R isn’t merely about expanding technical knowledge. It’s about appreciating the transformative power of a language specifically designed to unlock insights from data. In this blog post, we’ll dive into the nuts and bolts of R, unraveling its origins, exploring its key features and advantages, and understanding its pivotal role in the realm of data science. By the end of this guide, you’ll have a solid understanding of this potent, yet often under-appreciated, language and be one step closer to harnessing its power. 

What is R?

Often referred to as the “lingua franca of statistics,” R is an open-source programming language and environment designed specifically for statistical computing and graphics. R was conceived in the early 90s by Ross Ihaka and Robert Gentleman at the University of Auckland, New Zealand. It was their love for crafting a solution to handle data analysis with ease and precision that led to the birth of R.

R’s name itself is a clever nod to its origins, named after the first letters of its creators’ names, Ross and Robert. It’s also a playful homage to the S programming language, from which R draws much of its inspiration.

At its core, R is a reinterpretation of the S language — the pioneering language of statistical computing. But it’s not just a carbon copy. R enhances many aspects of S and adds its functionality, particularly in the area of data visualization, making it more adept at dealing with the complex, data-heavy tasks of today’s world.

The development of R was like throwing a pebble into a pond. The ripples it created extended far and wide, leading to the establishment of the Comprehensive R Archive Network (CRAN) in 1997. Today, CRAN serves as a vast repository of R packages contributed by developers worldwide, continually expanding R’s capabilities.

So, what started as a statistical language in the academic world has now evolved into a leading tool in data analysis and visualization, widely adopted across numerous industries. In the following sections, we’ll look at why R has gained such popularity and how it stands out in the programming world.

Key Features of R

R isn’t your average programming language. It’s a multifaceted tool tailored for data manipulation, analysis, and visualization. Here are some of the features that make R a standout choice for professionals working with data:

• Open-Source and Cross-Platform: Like many of its contemporary languages, R is open source, meaning its source code is freely available. This openness allows for continuous enhancements by its community of dedicated users and developers. Additionally, R is cross-platform, meaning it works smoothly on different operating systems, including Windows, Mac OS, and Linux.
• Powerful Statistical Analysis: R is a force to be reckoned with when it comes to statistical analysis. From simple descriptive statistics to advanced machine learning algorithms, R can handle it all. It’s like having a powerful calculator that can perform a myriad of statistical tasks.
• Data Visualization Capabilities: In data science, a picture is worth a thousand data points. R excels in creating high-quality, customizable graphics. Packages like ggplot2 offer advanced visualization capabilities, helping users create complex multi-layered graphs with relative ease.
• Comprehensive Packages: R’s power lies in its vast ecosystem of packages. The CRAN repository currently hosts over 15,000 packages, offering a diverse range of functions, from data manipulation to bioinformatics, web scraping to natural language processing, and much more.
• Reproducibility: R is highly favored in academic and research circles for its reproducibility. Researchers can bundle their data, statistical code, and the output of their analysis into a single document using R Markdown. This makes it easier for others to verify their results and fosters more transparent and reliable research.

Advantages of R

Understanding R’s features gives us a glimpse of its capabilities, but why exactly should someone choose R over other programming languages? Here’s a closer look at some of the advantages that R brings to the table:

• Unrivaled Support for Data Science and Statistics: Born from the world of statistics, R has a natural affinity for data science. It offers a wide array of statistical tests, model-building tools, and machine learning algorithms, making it a go-to language for data scientists and statisticians. Whether it’s data cleaning, exploration, visualization, or deploying complex models, R is designed to handle these tasks effortlessly.
• Wide Community and Support: With a large and active global community, finding support for R is never a problem. There are numerous online forums, tutorials, and resources to help you troubleshoot, learn new techniques, and stay updated with the latest developments.
• Compatibility and Interoperability: One of R’s strengths is its ability to play well with others. R can easily interface with other languages like C, C++, and Python. This flexibility makes R a great companion language that can fit seamlessly into a variety of workflows.
• Continuous Improvements and Updates: The open-source nature of R means that it is continuously being improved and updated by its user community. New packages are regularly added to CRAN, expanding R’s capabilities and keeping it at the forefront of statistical programming and data science.

Use Cases & Applications of R

R’s versatile nature allows it to be used across a myriad of industries. Let’s explore a few of these applications:

• Healthcare: In the healthcare sector, R is used to analyze patient data, predict disease outbreaks, and even identify patterns in DNA sequences. For instance, hospitals can use R to build models that predict patient readmission rates, helping to improve patient care and reduce costs.
• Finance: R’s powerful statistical capabilities make it a popular choice in the finance industry. It’s used for tasks like predicting stock prices, evaluating investment risks, and optimizing portfolios. By providing robust quantitative analysis, R helps financial analysts make informed decisions.
• Academia: Academic researchers heavily rely on R for a variety of tasks, from analyzing experimental data to testing new statistical methods. Its emphasis on reproducibility makes R an excellent tool for scholarly research, fostering transparency and reliability in academic findings.
• Tech Industry: In the tech world, R is utilized for machine learning, web analytics, A/B testing, and much more. Companies like Google and Facebook use R to understand user behavior and improve their services. 

The Current Hiring Outlook for R Programmers

Understanding the R language is more than just an academic exercise. It’s a skill that’s in high demand in today’s job market. Let’s unpack the current hiring landscape for those armed with R skills:

Why Businesses Are Looking for R Skills 

Given the importance of data-driven decision-making in today’s business landscape, companies are on the hunt for professionals who can turn data into insights. With its powerful data handling and statistical analysis capabilities, R has become a desirable skill for data analysts, data scientists, and statisticians.

Average Salary and Job Demand 

As per recent job market trends, the average salary for R programmers is quite competitive, often exceeding that of other programming languages. According to ZipRecruiter, the average salary of an R developer in 2023 is $123,147 per year. Demand for R programmers has also seen a steady rise — growing by 60 percent in 2022 — reflecting the increasing importance of data analysis and machine learning in various industries. 

The Significance of R in Hiring and Talent Acquisition

For hiring managers, candidates with R skills represent a valuable asset. These candidates are equipped to handle complex data tasks and derive actionable insights while brining a strong foundation in statistics. For job seekers, having R in your skillset is a powerful differentiator. It’s a clear indicator of your ability to tackle data challenges head-on and provide data-driven solutions.

Key Takeaways

As we wrap up this exploration of R, it’s clear that this language isn’t just a tool — it’s a powerhouse for data analysis, a cornerstone for statistical computing, and an essential skill in the evolving field of data science. Its versatile applications touch numerous industries, from healthcare and finance to academia and the tech sector.

And as we look to the future, the importance of R only seems to be growing. With an ever-increasing amount of data at our disposal, the need for capable, comprehensive tools to analyze and draw insights from this data is paramount. R, with its impressive suite of capabilities, is uniquely positioned to meet these challenges head-on.

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In a software development ecosystem dominated by mature, well-established programming languages, it’s a rare sight when a young newcomer makes a significant impact. Swift, however, managed to do just that. Despite its relative youth, Swift has rapidly become the heartbeat of the Apple universe, powering the devices and platforms we interact with daily — from iPhones and iPads to Macs and Apple Watches.

Swift, as its name suggests, is a speedy, powerful, and intuitive programming language. But it isn’t just about iOS apps; its versatility, efficiency, and safety make it a compelling choice for a range of applications beyond the Apple ecosystem.

In this article, we’re going to dive into the world of Swift, demystifying what makes this language tick and exploring how it’s used among developers. From the basics and key features to the exciting use cases and applications, this comprehensive guide will leave you with a better understanding of Swift’s role in tech innovation today and in the future. 

What is Swift?

Stepping into the spotlight at Apple’s Worldwide Developers Conference in 2014, Swift was born out of a desire to push the envelope in terms of what a programming language could be. It was meant to meld power and performance with simplicity, becoming a tool that could be picked up by both novice and expert developers alike.

One of the driving forces behind Swift’s development was the need for a more modern language to replace Objective-C, Apple’s primary programming language for iOS and macOS application development since the 1980s. While Objective-C had been a workhorse, it came with its fair share of complexities and issues. Its syntax was often considered cumbersome, and dealing with pointers and memory management was tricky, making the development process more error prone.

Swift, therefore, was conceived as a solution to these challenges — a language with a cleaner, more expressive syntax that would be approachable for newcomers yet deep enough to satisfy seasoned developers. It was designed to eliminate unsafe code, offer simplified memory management, and largely do away with common programming errors like null pointer dereferencing. Swift’s static typing system and error-handling mechanisms provided another layer of safety, catching bugs in the code at compile time rather than runtime.

Furthermore, Swift brought to the table some characteristics of scripting languages, like Python, making coding more interactive and fun. But while the syntax became more straightforward, Swift didn’t compromise on the high performance and efficiency expected from a systems programming language.

Key Features of Swift

Static Typing and Type Inference 

Swift is a statically typed language, which means that the type of a variable is known at compile time. This characteristic makes the language more predictable and the code easier to debug, as many errors are caught during the compilation process. Swift’s type system also includes type inference. So, if you declare a variable and assign it a value, Swift can infer the variable’s type based on its value. This reduces the verbosity of the code while retaining the benefits of a strong type system.

Optionals and Unwrapping 

Swift introduces a feature called optionals to handle the absence of a value. An optional represents two possibilities: either there is a value, and it equals x, or there isn’t a value at all. This is a significant improvement over languages like Objective-C where a nil (null) reference can lead to a runtime crash. In Swift, the compiler forces you to deal with optionals explicitly, thereby catching many potential issues at compile time.

Functional Programming Features

Swift combines the best of procedural and object-oriented paradigms with a sprinkle of functional programming features. It supports advanced features such as generics, closures (similar to lambdas in other languages), and first-class functions. These features offer a high level of abstraction, making Swift code more concise, flexible, and expressive.

Automatic Memory Management 

Swift uses Automatic Reference Counting (ARC) for memory management, reducing the cognitive load on developers. Unlike Objective-C, where developers had to manually manage memory, Swift handles memory allocation and deallocation automatically, reducing the chance of memory leaks and other common bugs.

Error Handling 

Swift provides robust and syntactic error-handling mechanisms. It includes a do-catch statement that allows errors to be “thrown” and “caught” for later handling. This feature ensures that when an error occurs, the software can continue to run and the error can be addressed in the best way possible.

The Advantages of Swift

Swift’s key features contribute to a slew of benefits that make it stand out among other programming languages. Here are some of its top advantages:

Speed and Performance

Swift was designed from the ground up to be fast. It offers performance that’s often better than that of its predecessor, Objective-C. In many cases, Swift’s performance is comparable to that of C++, which is known for its speed. Whether it’s complex object sort or simple computation, Swift’s speed and performance give it an edge.

Safety and Security 

Swift’s syntax and language constructions exclude several types of mistakes possible in Objective-C. It helps prevent errors such as null pointer dereferencing, which can lead to crashes. The type system and optionals make it less likely that you’ll overlook a potential problem. Plus, Swift’s automatic memory management helps avoid common memory errors.

Developer Productivity 

The simplicity of Swift’s syntax and its easy-to-read style make it a boon for developer productivity. Thanks to its concise yet expressive syntax, developers can write less code compared with other languages like Objective-C. Swift also includes modern features such as closures, multiple return types, and namespaces, which save time and reduce the chances of making mistakes.

Integration with the Apple Ecosystem 

Being Apple’s own programming language, Swift integrates seamlessly with the Apple ecosystem. Swift was built to leverage Cocoa and Cocoa Touch, Apple’s existing libraries for graphics, user interface, and more. It also comes with excellent support for all Apple platforms, be it iOS, macOS, watchOS, or tvOS.

Use Cases and Applications for Swift

From its inception, Swift has been steadily gaining popularity for a wide array of applications. Let’s explore some key areas where Swift shines.

iOS, macOS, tvOS, and watchOS Applications 

Swift is the go-to choice for Apple platform apps. From creating engaging apps for iPhone and iPad to developing sophisticated applications for Mac, Apple Watch, and Apple TV, Swift has it all covered. Companies like LinkedIn, Lyft, and Airbnb have all made the switch to Swift for their iOS apps because of its efficiency and speed.

Server-Side Development 

Swift isn’t just for building user-facing apps; it’s also carving out a space in server-side development. Its strong performance characteristics make it a great choice for building fast and safe server-side applications. IBM has backed Swift in the cloud with its Swift server-side framework, Kitura, and there’s also Vapor, another popular server-side Swift framework.

Accessible Coding Education 

Swift has also found a home in the education space. Swift Playgrounds is an app for iPad and Mac that makes learning Swift interactive and fun. It requires no coding knowledge, so it’s perfect for students just starting out, regardless of age. The guided lessons teach key coding concepts, and additional challenges and templates encourage students to explore code in exciting new ways and to create something completely unique. This educational bent showcases Swift’s accessibility and the broader initiative to introduce more people to coding.

Key Takeaways

As we wrap up our deep dive into Swift, it’s clear that this language has made a significant mark on the world of software development. Combining performance, safety, and expressiveness, Swift has made the process of coding more efficient and fun, from the realms of Apple’s own ecosystem to server-side development and even educational environments.

Given the ubiquitous nature of Apple’s products and the key role Swift plays in the development of its software, the popularity of this language isn’t just a passing trend. Behind it lies a vibrant and active developer community, which translates to readily available talent, a wealth of shared knowledge, and countless resources for innovation. Moreover, the language’s emphasis on safety and performance lends itself to the creation of high-quality, efficient applications. This is a win-win situation for those who build the software and the end users who interact with it.

While Swift might be considered a relative newcomer in the grand scheme of programming languages, it’s already demonstrated its strength as an intuitive and powerful language. It’s up to the task of propelling the next generation of applications for Apple platforms — and beyond — and will continue to hold a prominent place in the software development landscape.

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The programming language C stands as a key pillar in the world of computer science, remaining valuable even as the tech industry continues to evolve. Its flexibility, efficiency, and its influenceon many other languages make it a foundational skill for many developers, and a language of choice for system programming, embedded systems, and more

Having a firm grasp of C can open doors to numerous opportunities. It’s a language that often acts as a stepping stone to others, giving developers a more in-depth understanding of how computers really work. For instance, it provides first-hand experience with concepts like memory management, pointers, and low-level access to system resources that are abstracted away in many high-level languages. This proficiency in C can significantly improve programming capabilities overall, resulting in better code efficiency and optimization in whichever language you work in next.

But for those aspiring to ace a C programming interview, it’s essential to move beyond the basics. One must challenge their coding abilities and practice working on the types of problems likely to be encountered in an interview setting. Here, we’ll discuss the details of the C language, explain what a typical C interview looks like, and provide a series of challenging C interview questions to help you sharpen your skills and stand out. 

What is C?

Created in the early 1970s, C is a general-purpose language with features that allow developers to build programs operating directly on a physical machine’s level. Due to its low-level capabilities, C has been instrumental in writing system software, enabling the development of compilers, interpreters, operating systems, and database systems.

C’s syntax is simple, making the language easy to learn and use. However, don’t let the simplicity fool you. C’s low-level nature and access to memory management, combined with its simplicity, make it an efficient language for creating fast, compact programs.

A distinct feature of C is its ability to manipulate system hardware directly through the use of pointers. This characteristic makes it invaluable for applications that require high performance or that operate at a system level, such as creating desktop applications, game development, and implementing other programming languages.

What a C Programming Interview Looks Like

A C programming interview often involves a range of elements. While the specific format may vary from company to company, you can generally expect a combination of coding exercises, problem-solving questions, and conceptual discussions. 

In coding exercises, you’ll be tasked to write C programs or functions that solve a specific problem or perform a particular task. These challenges can range from data structure and algorithm problems to system-level tasks, reflecting the range of applications where C shines. It’s also not uncommon to face questions involving memory management or pointers, given their significance in C.

The problem-solving questions are aimed at assessing your logical thinking and approach to software design. You might be presented with a high-level problem and asked to outline how you’d tackle it using C. This could involve discussing the data structures you’d use, the algorithms you’d implement, and how you’d ensure your solution is efficient and robust.

Conceptual discussions focus on your understanding of C and its various constructs. You might be asked about how certain features of C work, like its memory management system, how pointers function, or the purpose of specific keywords. It’s crucial to not only know how to use C but to understand how it works behind the scenes.

C Interview Questions

In this section, we’ll dive into a series of C interview questions, starting from an intermediate level and getting progressively tougher. Remember, the goal isn’t to breeze through these questions, but to stretch your C programming skills and prepare you for the types of challenges you might encounter in a real-life interview.

1. Array Rotation

Task: Write a C function named ‘rotate’ that takes an array and its length as input and rotates the array in-place to the right by one position.

Input Format: The input will be an integer array and its length.

Constraints: The array length will be at least 1.

Sample Input: int arr[] = {1, 2, 3, 4, 5}; int n = 5;

Array after rotation: 5 1 2 3 4

Sample Code:

void rotate(int arr[], int n) {

   int temp = arr[n-1], i;

   for (i = n-1; i > 0; i--)

      arr[i] = arr[i-1];

   arr[0] = temp;

}

Explanation: 

The ‘rotate’ function temporarily stores the last array element to prevent data loss during the shifts. Next, using a for loop, it moves all the elements one step to the right. Finally, it places the saved element at the array’s start, completing the rotation.

This question tests the candidate’s ability to work with arrays and manipulate them, a fundamental skill in C programming. It mimics real-world scenarios where developers often need to shift, rotate or rearrange data stored in arrays. 

2. String Palindrome

Task: Write a C function named ‘isPalindrome’ that checks whether a given string is a palindrome or not.

Input Format: The input will be a string.

Constraints: The string will only contain alphanumeric characters.

Output Format: The function should return 1 if the string is a palindrome and 0 otherwise.

Sample Input: racecar

Sample Output: 1

Sample Code:

int isPalindrome(char* str) {

    int l = 0;

    int h = strlen(str) - 1;

 

    while (h > l)

    {

        if (str[l++] != str[h--])

        {

            return 0;

        }

    }

    return 1;

}

Explanation:

The ‘isPalindrome’ function first finds the length of the string and sets two pointers, one at the start (l) and one at the end (h). It then compares the characters at the positions pointed by ‘l’ and ‘h’. If they are not the same, it returns 0, indicating that the string is not a palindrome. If they are the same, it increments ‘l’ and decrements ‘h’ and repeats the comparison until ‘h’ is less than ‘l’, at which point it returns 1, confirming that the string is a palindrome.

This question tests a candidate’s understanding of string manipulation and comparison, fundamental tasks in many real-world applications. Well-crafted solutions demonstrate the candidate’s proficiency with string operations and working with pointers in C.

3. Linked List Reversal

Task: Write a C function called ‘reverseList’ that reverses a linked list.

Input Format: The input will be a pointer to the head of a singly linked list.

Sample Input: 1 -> 2 -> 3 -> 4 -> NULL

Linked list after rotation: 4 -> 3 -> 2 -> 1 -> NULL

Sample Code:

typedef struct Node {

    int data;

    struct Node* next;

} Node;




void reverseList(Node** head_ref) {

    Node* prev   = NULL;

    Node* current = *head_ref;

    Node* next = NULL;

    while (current != NULL) {

        next  = current->next;  

        current->next = prev;   

        prev = current;

        current = next;

    }

    *head_ref = prev;

}

Explanation:

The ‘reverseList’ function reverses a linked list by reassigning the ‘next’ pointers of each node. It iterates through the linked list, starting at the head, and in each iteration, it reassigns the ‘next’ pointer of the current node to the previous node. After each iteration, it moves to the next node by following the original ‘next’ pointer, which it saved before reassignment. When it reaches the end of the list, it assigns the ‘prev’ node as the new head of the linked list.

This question tests a candidate’s proficiency with pointers and dynamic memory allocation, and their understanding of complex data structures like linked lists, skills often necessary when working with C in system-level programming.

4. Calculate the Nth Term

This challenge will help you test your understanding of recursion.

A function that calls itself is known as a recursive function. The C programming language supports recursion. But while using recursion, one needs to be careful to define an exit condition from the function, otherwise it will go into an infinite loop.

To prevent infinite recursion, an ‘if…else’ statement (or a similar approach) can be used where one branch makes the recursive call and the other doesn’t.

void recurse() {

    .....

    recurse()  //recursive call

    .....

}

int main() {

    .....

    recurse(); //function call

    .....

}

Task: There is a series, ‘S’, where the next term is the sum of previous three terms. Given the first three terms of the series, ‘a’, ‘b’, and ‘c’ respectively, you have to output the nth term of the series using recursion.

Input Format: The first line contains a single integer, ‘n’. The next line contains 3 space-separated integers, ‘a’, ‘b’, and ‘c’.

Constraints:

• 1 ≤ n ≤ 20
• 1 ≤ a,b,c ≤ 100

Output Format: Print the nth term of the series, S(n).

Sample Input:

5

1 2 3

Sample Output: 11

Explanation:

Consider the following steps:

1. S(1) = 1
2. S(2) = 2
3. S(3) = 3
4. S(4) = S(3) + S(2) + S(1)
5. S(5) = S(4) + S(3) + S(2)

From steps 1, 2, 3, and 4, we can say S(4) = 3 + 2 + 1 = 6; then using the values from step 2, 3, 4, and 5, we get S(5) = 6 + 3 + 2 = 11. Thus, we print 11 as our answer.

Solve the problem.

5. Implementing a Stack

Task: Write a C program to implement a stack using a linked list. Your program should have ‘push’ and ‘pop’ operations.

Input Format: The inputs will be the elements to be pushed to the stack.

Output Format: The outputs will be the elements popped from the stack.

Sample Input: push(1), push(2), push(3), pop(), pop()

Sample Output: 3, 2

Sample Code:

typedef struct Node {

    int data;

    struct Node* next;

} Node;




Node* top = NULL;




void push(int data) {

    Node* newNode = (Node*)malloc(sizeof(Node));

    if (!newNode) {

        printf("Heap overflow");

        exit(1);

    }

    newNode->data = data;

    newNode->next = top;

    top = newNode;

}




int pop() {

    Node* temp;

    int poppedValue;




    if (top == NULL) {

        printf("Stack underflow");

        exit(1);

    }

    else {

        temp = top;

        top = top->next;

        poppedValue = temp->data;

        free(temp);

        return poppedValue;

    }

}

Explanation:

The given code demonstrates the implementation of a stack data structure in C using a singly linked list. The ‘push’ function creates a new node, checks if memory allocation was successful, and if so, assigns the input data to the new node and adds it to the top of the stack. The ‘pop’ function checks if the stack is empty and if it isn’t, removes the topmost node from the stack, returns its value, and frees the memory allocated to it.

This question tests a candidate’s understanding of fundamental data structures (like stacks) and their implementation in C, along with the use of dynamic memory allocation. Successfully tackling this problem demonstrates proficiency in handling memory, managing pointers, and understanding the lifecycles and behaviors of data structures, which are crucial for low-level and system programming tasks in C.

6. Binary Tree Traversal

Task: Write a C function named ‘inorderTraversal’ that performs an in-order traversal of a binary tree.

Input Format: The input will be a pointer to the root node of a binary tree.

Output Format: The function should print the nodes of the binary tree in an in-order traversal sequence.

Sample Input: Binary tree with nodes arranged as follows: 1 (root), 2 (left child of 1), 3 (right child of 1)

Sample Output: 2, 1, 3

Sample Code:

typedef struct Node {

    int data;

    struct Node* left;

    struct Node* right;

} Node;




void inorderTraversal(Node* root) {

    if (root != NULL) {

        inorderTraversal(root->left);

        printf("%d ", root->data);

        inorderTraversal(root->right);

    }

}

Explanation:

The ‘inorderTraversal’ function uses recursion to traverse a binary tree in in-order fashion, which means visiting the left subtree, the root node, and then the right subtree. If the given root node is not null, the function recursively calls itself to visit the left subtree, then it prints the root’s data, and finally, it calls itself again to visit the right subtree.

This question tests a candidate’s understanding of binary trees and their traversals, along with the concept of recursion. It’s a commonly asked question in C interviews because these are fundamental concepts often utilized in many computer science problems. 

7. Hash Table Implementation

Task: Write a C program to implement a simple hash table. This hash table will use chaining to handle collisions.

Input Format: The input will be the keys and values to be inserted in the hash table.

Output Format: The program should be able to retrieve values given the keys.

Sample Code:

#include <stdlib.h>

#include <string.h>




typedef struct node {

    char* key;

    char* value;

    struct node* next;

} node;




typedef struct hashtable {

    int size;

    struct node** table;

} hashtable;




hashtable* createHashtable(int size) {

    hashtable* newTable;

    if (size < 1) return NULL;

    if ((newTable = malloc(sizeof(hashtable))) == NULL) {

        return NULL;

    }

    if ((newTable->table = malloc(sizeof(node*) * size)) == NULL) {

        return NULL;

    }

    int i;

    for (i = 0; i < size; i++) {

        newTable->table[i] = NULL;

    }

    newTable->size = size;

    return newTable;

}




unsigned int hash(hashtable* hashtable, char* key) {

    unsigned int hashval = 0;

    for (; *key != '\0'; key++) {

        hashval = *key + (hashval << 5) - hashval;

    }

    return hashval % hashtable->size;

}




node* createNode(char* key, char* value) {

    node* newNode;

    if ((newNode = malloc(sizeof(node))) == NULL) {

        return NULL;

    }

    newNode->key = strdup(key);

    newNode->value = strdup(value);

    newNode->next = NULL;

    return newNode;

}




void set(hashtable* hashtable, char* key, char* value) {

    unsigned int bin = hash(hashtable, key);

    node* newNode = createNode(key, value);

    newNode->next = hashtable->table[bin];

    hashtable->table[bin] = newNode;

}




char* get(hashtable* hashtable, char* key) {

    unsigned int bin = hash(hashtable, key);

    node* pair = hashtable->table[bin];

    while (pair != NULL && pair->key != NULL) {

        if (strcmp(pair->key, key) == 0) {

            return pair->value;

        }

        pair = pair->next;

    }

    return NULL;

}

Explanation:

The provided code demonstrates the implementation of a simple hash table with chaining in C. It includes the creation of a hash table, generation of hash values from keys, and insertion and retrieval of key-value pairs. The hash table uses a simple hash function to convert keys into indices. If collisions occur (when different keys result in the same index), chaining is used by maintaining a linked list of key-value pairs for each index in the hash table.

This question is challenging because it involves various crucial concepts in C: dynamic memory allocation, pointers, linked lists, and data structures. Hash tables are widely used due to their efficiency in key-value pair storage and retrieval. 

Resources to Improve C Knowledge

• HackerRank C Practice Questions
• HackerRank Interview
• Tech Interview Prep: How To Ace Your Interview

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